1. Field of the Invention
This invention relates to advanced military grade communications jamming systems and, more specifically, to a System and Method to Autonomously and Selectively Jam Frequency Hopping Signals in Near Real-time. This unique state-of-the-art invention will have widespread use in any modem military organization that wants to achieve communications dominance and information superiority over any battlefield. The invention will add an essential, and much needed, communications and electronic warfare capability to any respective governments' national defense program.
2. Description of Related Art
Modem military grade communication systems today employ short, burst type transmissions that constantly cycle through a secret sequence of frequencies in order to prevent detection and jamming. Such systems are commonly known as frequency hoppers. Typically, these systems (both foreign and domestic) only transmit on a particular frequency for no more than a few milliseconds at the most. This creates a problem for those who want to detect and jam such transmissions as they happen so quickly. Practically, it is not feasible to simply “splash” the radio frequency spectrum with random noise in order to jam such transmissions. The reasons are that it requires an unpractical amount of power to apply sufficient RF energy to wash out all transmissions. In addition, there may be friendly transmissions that should not be jammed. Also, since the duration of the target transmissions is so short, it is not practical to have (for instance) a CPU that is programmed to evaluate signals, make a determination, and then command transmitters to jam. There is simply not enough time to engage the frequency hopping signals before they have moved on to a new frequency.
What is needed therefore in order to feasibly detect and jam these modem fast hopping transmissions is a System that has: 1) The ability to capture wide bandwidth regions of the RF spectrum instantaneously; 2) The ability to automatically discover (without CPU intervention) sudden, short duration signals as they appear; 3) The ability to automatically determine (without CPU intervention) if the signal should be jammed or not; 4) The ability to autonomously command (without CPU intervention) the jamming equipment to transmit on the appropriate frequencies; and 5) The ability to do all of these functions in near real time from the moment the signal is received.
The prior-art of FIG. 1 is a present-day jamming system. In order to find a target signal, an operator tunes the receiver. It is then up to the radio operator to manually determine if this newly captured signal should be jammed or not. If not, then the radio operator continues to search for new signals. But if the signal is determined to be a target that should be jammed, then the operator sets the controls of his jamming equipment and transmits appropriately. Periodically, the operator stops jamming to see if the signal is still present. Such an operation is called a “look-through” and is necessary in case the target has moved to a new frequency.
Such a traditional setup is suitable for the detection of relatively long duration communication signals such as voice or a low speed data links. But this simple system has several drawbacks including the fact that sudden, short duration signals are extremely unlikely to be captured. In addition, even if a short-duration signal is captured, it is impossible for the radio operator to manually jam the transmission in such a short period of time. Such systems are the oldest kind and are inadequate to jam today's modern military grade frequency hopping radios.
FIG. 2 is a flowchart depicting the functional method 76 of the system of FIG. 1. First, the operator detects a target signal 300 (manually); after deciding to jam the target signal 302, the operator must tune the jamming transmitter to the target signal's frequency 304. When ready, the operator turns on the jamming transmitter to transmit a jamming signal on the target signal frequency 306. As discussed above, periodically the operator must cease transmitting for a short time 308 so that he or she can “look through” for the target signal to see whether or not it is still transmitting on the original frequency 310. If it is still transmitting 312, the operator will re-commence transmitting a jamming signal on the original frequency 306. If, however, the target signal is not up on the same frequency 314, the operator will recommence detect/listen mode 300 and attempt to find the target signal on a new frequency (or another target transmitter).
The prior-art of FIG. 3 is a more elaborate present-day jamming system. The typical system uses a fast scanning receiver to quickly sweep through the RF spectrum looking for signals. Once captured, the frequency setting of that signal is “handed-off” to a CPU whose purpose is to determine if the signal should be jammed or not. This function is typically pre-programmed so as to not require manual intervention and speed up the turnaround time. The CPU then commands the jamming equipment to transmit as programmed.
But again, this prior-art system has many of the same drawbacks as the system of FIG. 1, including the fact that sudden, short duration signals are still very unlikely to be captured. The frequency hopping signals are on the order of milliseconds or less per “hop”. Thus, the sweeping receiver must be sweeping past at the right time and at the right place where the signal appears, otherwise the hop will be missed. Also, the CPU cannot process and execute functions in less than a millisecond. Thus, the latency of this system is inadequate to jam short duration signals.